The national scheme was launched jointly by Portsmouth City Council and Hampshire County Council, and challenges children to read at least six library books and collect a wall chart and stickers as they go.

All children completing the free challenge will earn a medal and a certificate, and children in Portsmouth will receive an invitation to the exclusive winners' event at Southsea Castle on September 20.

Research shows how important reading for pleasure is for children's life chances, and the Summer Reading Challenge has been shown to improve children's reading range, confidence and enjoyment.

It will also help parents keep their children happily occupied over the six-week summer break.

This year's reading challenge, Team Read, has a sporty theme to tie it in with Beijing Olympics, to be held next month, and the growing excitement about the London 2012 Olympics.

The challenge is part of The News Spread the Word literacy campaign.

Lindy Elliott, from the city council's library service, said: 'Becoming a Team Read winner this summer will be a great way to celebrate the 2008 National Year of Reading. It will help children maintain and develop their reading skills, and during a period in the year when there is no school work they can really indulge the pleasure of reading for fun.

Children of all ages can take part in Portsmouth but only children aged from four to 11 years can do so in Hampshire.

But they can choose what books to read – whether they are by a favourite author or information books.

All Portsmouth libraries are also offering a range of free activities, all based on a sports theme.

Portsmouth North MP Sarah McCarthy-Fry has backed the scheme.

She attended a House of Commons reception for the national launch of the challenge.

She said: 'I am delighted by this year's sporting theme, and hope it will encourage more children than ever to join in.

'The challenge should keep the children of Portsmouth North interested throughout the long summer holidays. It could help develop a positive attitude to leisure time which they will take with them into adult life.'