The Hutt South electorate MP broke his right shoulder blade and right thigh bone after tumbling off his bike on Saturday morning taking part in Cycling Otago's R and R Sport Tour on the Taieri Plain.
During surgery that day he had a plate and screws inserted into his right femur, or thigh bone.
Mr Mallard said he was going just over 40kmh on Huntly Rd, keen to catch the next bunch of riders, when his wheel clipped another cyclist's.
He and two others hit the ground.
The others were unhurt.
He had been trying to regain his place in the race after losing time helping cyclists who had crashed.
"[After hitting the ground] I started to stand up, and sat down again very quickly."
Although in considerable pain, he was conscious throughout his ordeal and said he was lucky St John had just finished a job in Mosgiel and he could be transferred to hospital in good time.
He felt "quite embarrassed" about the incident, and was trying to keep in touch with his work by cellphone and computer.
Yesterday, Mr Mallard, Labour's Rugby World Cup spokesman, was to have toured the Forsyth Barr Stadium to see the progress on its construction.
Mr Mallard, who was closely involved in New Zealand's successful bid for the Cup in 2005, said he would not "second guess" where Christchurch's five pool games would now be played but "I hope and would expect Dunedin would get one extra match at least".
It was a complicated logistical matter for Cup organisers to decide, and although it would not be feasible to do so, it would be easier if they could clear the schedule and start all over again from scratch, he said.
Mr Mallard said he did not know when he would be discharged from hospital, or when he could head back to Wellington.
He hoped to be back on the job within a fortnight.
Getting back on his bike might take longer, especially with this November's general election his main focus.
He hoped to make the Taieri Plain event his focus for his first foray back into competitive cycling.
