It is a sector which has seen relentless growth in recent years but most of the investment has been focused on Martin Goymour's stable of attractions, Banham Zoo and Africa Alive, near Lowestoft.

Now the newest kid on the block, Cromer's Amazona Zoo, and Thrigby Hall Wildlife Gardens near Great Yarmouth are to see major new developments ahead of the summer season.

Conservation veteran Ken Sims, 72, opened Thrigby Hall at Filby in 1979 as a home for Asian wildlife and spent more than £1m in launching Amazona Zoo for South American stock in 2008.

Partly with an eye to retirement, he has now decided to focus his investment on Thrigby Hall and has announced the sale of Amazona Zoo for an undisclosed figure to the Hall Road site's landlord, Benjie Cabbell-Manners, of Cromer Hall.

For Mr Cabbell-Manners, the venture will be his latest – and most creative –estate diversification which has already seen him build industrial units, a short-term travellers' site and petrol station.

He said: 'The estate goes right into the middle of Cromer and it is really important to consider that tourism, not farming, is Norfolk's most important industry these days.

'If we want the estate to survive we have to do everything.'

He said when Mr Sims had first approached him about developing the zoo on the 15-acre site he had been '100 per cent behind it'.

'Amazona Zoo is one of the finest attractions in north Norfolk so after many years under the loving ownership of Ken Sims we're very proud and excited to be taking it on,' he said.

His wife Dido and children Rupert, 23, Jessica, 23, and Hughie, 20, would all have a part to play in running the zoo which has five permanent staff.

He said: 'We have a number of short and long term plans to enhance the zoo. This year we're launching a new soft-toy centre for young children as well as a large yurt 'education centre' for events, parties and functions. 'These indoor spaces will create more options for families when the weather is against us and will make Amazona more of a year-round attraction.'

He said the restaurant was being refurbished to portray a more authentic slice of the Amazon rainforest – 'like the Rainforest Cafe in London' –and a long-term goal was to eventually use meat and other produce from their own farm.

He said: 'We've worked with animals all our lives so we see the great potential in the zoo, so much so that in May we're taking a trip to South America to bring back new ideas and inspiration.'

Their ambitious goal in the longer term was to increase visitor numbers from the present level of 33,000 to 95,000 per year.

'We hope that our substantial investment plus our ambitions to integrate the zoo further into community life will make Amazona an unmissable attraction for visitors as well as residents of Cromer,' he said.

'We want Cromer to be proud of their zoo. When the town is doing well we tend to do well as an estate. We have had nothing but support from everybody in the area.'

The immediate improvements would involve an investment of 'tens of thousands of pounds' and if zoo visitor numbers took off, an expansion of the site would be considered.

In due course opportunities would arise to expand the variety of species and the zoo would also look to further breeding success following the birth of a puma cub last year.

Mr Cabbell-Manners said they also planned to extend the zoo's opening season which currently stretched from Easter through the October half-term.