Hi , I am assuming it's a gas oven, if not get a cooker repair guy in asap and don't use. If it is gas hen the following applies .
Hi , I would not use it till the cause is found as it is most likely emitting carbon monoxide aswell, which is a deadly gas. Look at the flame . it should be blue, with no yellow flame . The burner could be cracked. I recommend getting a gas safe engineer who works regularly on gas cookers to look at it . the burner will need to be removed to check it and the air vents behind and under the cooker checked to make sure they are clear. Gas safe have a search facility to find a local guy to help. I'm sorry to say ,this cooker oven is extremely Dangerous and please don't use.