If it goes ahead, it could create several hundred permanent jobs, as well as those needed during construction.

Two rival property groups, Dunloe Ewart and John Laing Property are coming together to make a £400m investment.

Initially, the groups had proposed two separate development schemes.

The plans include an extension which will double the size of the Castle Court shopping centre, as well as development of a nearby site on Royal Avenue, one of the city's main shopping areas.

Amalgamation was on cards

Until now, four rival proposals for major new shopping developments in Belfast were at the planning stage.

Most property experts felt this was too many and there was an expectation that some amalgamation would have to take place.

Frank Caddy of Belfast Chamber of Commerce said: "We have seen 10 years of nothing and now we have four proposals. Had they been introduced more gradually, maybe two, possibly three of them could have gone in."

High level of investment

At a news conference in Belfast, Noel Smyth, Dunloe Ewart's chairman, said: "By pooling our resources, I believe we can create one of Europe's most exciting city centre retail and leisure schemes.

"Belfast is undergoing rapid change because of the high level of investment both in the city and in the north of Ireland generally."

Details of how the schemes will be linked have still to be worked out.