Work in the main bowl area of Auckland's new Vector Arena returned to normal yesterday after weekend work on modifications to its giant roof truss.

Roger Feast, Mainzeal Construction's Auckland area manager, said remedial work had been completed and the full building team was back on the job near the old Auckland Railway Station.

Work stopped late last week and most of the arena's builders left the job after structural problems were found with the main curved roof truss.

A full complement of builders and sub-contractors was due back on the site yesterday.

An engineering report on the arena's roofing elements recommended strengthening to the ceiling beam which spans the 120m-long stadium at Quay Park.

Feast said the work involved "minimal plate welding".

Mainzeal's consulting engineer on the job, Graham Voysey of civil and structural engineers Holmes Consulting, said all comments must come from the builder.

Mainzeal's problems on the Auckland job are being compared with Multiplex's problems in putting up Wembley Stadium in London.

Cost over-runs, lateness and a series of unexpected events had dogged both projects.

Mr Feast issued a statement last week describing major company restructuring at Mainzeal which he said was "great news" for the builder, particularly the prospect of building in Shanghai.

Richard Yan, managing director and chief executive of Richina Pacific, which owns Mainzeal, said the builder would complete $550 million of work this financial year and around $500 million next year.

Richina estimates Mainzeal lost $12 million in the past year on the arena and the Scene apartment buildings on the waterfront.

Mr Feast said it was "business as usual" for Mainzeal's offices in Auckland, Hamilton, Palmerston North, Wellington and Christchurch while the restructuring was going on.

Neil Ranford, the chief executive of Mainzeal, has left the company.

Last year, the Rolling Stones and U2 were tipped to play at the arena, subject to what Vector Arena chief executive Bruce Mactaggart said were issues including timing and economics.

The Rolling Stones will play at Western Springs in Auckland this weekend.

The troubles

Wembley, $2b:
* 90,000-seat stadium, London.
* Cost and time problems.
* Due to be finished last year.
* Builder Multiplex hard hit.
* Boss John Roberts quit last year.
* Site workers evacuated in March.
* Roof problems - dropped 1m.

Vector arena, $80m:
* 12,200-seat indoor arena, Auckland.
* Cost and time problems.
* Due to be finished 6 months ago.
* Builder Mainzeal hard hit.
* Boss Neil Ranford has just left.
* Site workers evacuated last week.
* Roof problems - strengthening needed.