"We can't disclose it. However, it is substantial and certainly more than we first envisaged," he said.
Wanganui company W&W; Construction has been awarded the contract to earthquake-strengthen the site to 67 per cent of the National Building Standard (the Wanganui District Council requires a minimum 33 per cent rating) and to refurbish and future-proof the buildings with work to start shortly.
Most of the 56-bed rooms will have en suites and Mr Tucker said they would be advertising that bed space late July or early August.
Mr Tucker said the refurbishment aimed to retain the "charm and memories that the Aubert Home of Compassion was known for".
"We're also very pleased to know that the building work Revamp begins for will create a number of jobs for Wanganui," Mr Tucker said.
Local architect Robert Jaunay, of Stapleton Elliot, is overseeing the project which will see the first stage completed by the end of July in time to open in early August.
Mr Tucker said a start on the second and final stage and was probably 12 months away. That stage will see a few more beds added and the chapel on the site rebuilt.
Andrea Bunn, Wanganui District Health Board health of older people spokeswoman, said WDHB staff had met with the Tuckers to agree on what needed to be done for the new owners to secure a contract from the board.
"This includes the need to meet the Ministry of Health's certification requirements," Mrs Bunn said.
When the makeover is finished the complex would have both a rest home and a hospital wing with at least 50 staff employed.
In addition to the St John's Hill Healthcare, the Tuckers own Rosewood Resthome and Hospitals in Christchurch.