MPs from across all parties have launched a group to "drive business, skills and economic growth" in the north of England.
The Northern Powerhouse parliamentary group aims to attract investment and highlight issues affecting the region.
It was set up by the Northern Powerhouse Partnership, a body chaired by former chancellor George Osborne.
It comes after Manchester mayor Andy Burnham said the country was still "too London-centric".
The Northern Powerhouse was a concept created by Mr Osborne in 2014 as an attempt to "rebalance" the UK's economy away from being dominated by London and the South East.
Conservative MP for Carlisle John Stevenson – who chairs the new group – said it aimed to "increase investment in and awareness of the North as a place that drives business, skills and economic growth".
Steve Rotheram, the Labour mayor of Liverpool city region, said it was "vitally important" that the widest possible coalition was built in support of "economic rebalancing" and that the case for the Northern Powerhouse was advocated in the north and "at the centre of national political decision-making".
Northern Powerhouse minister Jake Berry said he hoped the group would help to turn the north of England into a "globally-recognised economy".
But responding to the Budget on BBC One's Sunday Politics, Andy Burnham, the Labour mayor of Greater Manchester, said he wanted to see "a more wholehearted embrace of devolution" from both the Conservatives and Labour.
"We are too London-centric," he said.
"Brexit is looming. We need investment in the regions. I don't think we can bring all of this power back from Brussels and keep it in Westminster."
Former cabinet minister Lord Heseltine, who led a review into economic growth and recommended the creation of combined local authorities, also said it was of the greatest importance to break the monopoly of power in London.
However, the Conservative peer told BBC Radio 4's the Westminster Hour that devolution in England needed to go further.
"We have got mayoral authorities – I believe there is improvement coming – but look at Leeds, Sheffield, Newcastle, South Hampshire, South Devon. There is no devolution of any great consequence there."
There are more than 600 all-party parliamentary group (APPGs), which have no formal status in Parliament but are used by MPs and others to raise awareness of a wide range of issues.