An increase in the number of hand, foot and mouth disease (HFMD) patients in the North Island has Bay of Plenty health officials urging parents and daycare centres to enforce children's hygiene.

In the last month Tauranga Hospital has treated around 20 children, aged between two and five-years-old, suffering from dehydration as a result of the contagious virus.

Bay of Plenty health officials say the easiest way to prevent hand, foot and mouth disease is hand washing and good clean personal hygiene.

Media are also reporting Auckland Starship Hospital's emergency department has been treating up to 15 children each week for the last month.

The disease, a contagious virus based in the intestine, is not the same as the veterinary disease, foot and mouth and is characterised by fluid-like blisters appearing on the hands, feet and inside of the mouth.

It is not considered serious but many children can become dehydrated as blisters make it painful to drink water.

Bay of Plenty District Health Board paediatrician Doctor Hugh Lees says while it is contagious it is considered relatively mild.

'We only see the children who are having difficulty with getting fluids. Most children will probably be being seen by a GP.

'The most important measure to prevent the spread is "to wash your hands.”

Health officials are advising children should only be sent home if they are feeling unwell, not because red spots are visible.

HFMD most commonly affects children under the age of 10, particularly pre-schoolers with outbreaks often occurring in chid-care centres and schools.

The disease is transmitted from person to person by direct contact with the blisters fluid or direct contact from secretions from the child's nose or throat.

Bay of Plenty Medical Officer of Health Doctor Phil Shoemack says with any contagious or viral disease it is important not to let personal hygiene slip.

'It's really important that we don't forget its importance whether that's with respect to preventing hand, foot and mouth, influenza or tummy bugs.”

He believes 'every day good personal hygiene” cannot be overlooked and responsibility starts with parents and caregivers.

It just can't be over-emphasised the importance of good every good personal hygiene and one of the key things is hand washing.

'There are things we can do to assist young children stop spreading the infections. One of which is that we should stop sending young children if they have an infectious disease along to any sort on communal setting whether that be day care, kindy, a party.

'Or even if you know they have an infectious disease don't send them to the next door neighbours.”