A "mindset shift" is needed across the UK's central government to help Number 10 North deliver its objectives, its deputy director has said.

Duncan Parish told a conference in Lincolnshire on Wednesday there were "institutional challenges" within government that needed to be overcome to deliver change.

The Manchester office of Number 10 North - sister to London's Downing Street - was set up by Prime Minister Andy Burnham in July.

Burnham's political opponents have called the office a "gimmick" and raised transparency concerns about the costs involved.

Speaking to the Great Exhibition conference of local political and business leaders, Parish said his career in the civil service to date had "not been without its frustrations" and there can be "friction" between different parts of government which have "similar but ever so slightly competing objectives".

Parish, a civil servant in Whitehall before moving to Manchester four years ago, said Number 10 North staff were "delivering outcomes at a national level across a huge range of areas" including health, transport, education and social care. "But we continually need to work to overcome those institutional challenges," he added.

He said one priority of Number 10 North was to "shift power and accountability" closer to local areas, but acknowledged "that means reforming the civil service as well" - by not viewing national, regional and local government as separate.

Describing Number 10 North's second focus of growth, Parish told local leaders: "We're here to unblock issues that may have become stalled or where boundaries within government end up being a hindrance." He said that "too often, working within government or departments can be perceived as either difficult or slow".

"But to deliver that change, requires us all to change - and part of that change is a mindset shift within central government," he said.

"We need to focus on the whole country and work across those boundaries, bringing in mayoral strategic authorities like Greater Lincolnshire into discussions that previously they may not have been part of - working bottom-up, rather than top-down." His comments come as the government continues to face questions about the cost to the taxpayer of the new headquarters.

In September, Conservative shadow minister Mike Wood raised concerns about "little information and so little transparency" surrounding Number 10 North which he described as a "gimmick".

"The minister either doesn't know or won't tell us how much No 10 North will cost, how many people work there or how many of them actually turn up to work - it's almost as though this hasn't been properly thought through," he told a House of Commons debate.

He called for the annual budget, staff levels and office attendance statistics to be published. Current staffing levels have also not yet been clarified.

Cabinet Office minister Sally Jameson said last week that the government did not know how much has been spent on hotels for No 10 North staff, ministers and special advisers travelling between London and Manchester since it opened.

The cost is "not centrally collated" but is "being met within existing departmental budgets", Jameson said in response to a parliamentary question.

Number 10 North's latest summit of regional mayors, held in its "situation room", will take place on Thursday. Burnham has previously indicated he will work there at least once a week, and hosted the Irish Taoiseach Micheál Martin in September.

Parish added in his speech: "How will we know if Number 10 North is working?

"Ultimately, success will be in people in the UK feeling the difference in their communities, with greater opportunities, improved living standards, faster decisions...more joined up services and a stronger voices in the future of their place."